Hair spring and balance wheel timing mechanism



Sept. 9, 1952 F. J. CALDWELL 2,509,630

HAIR SPRING AND BALANCE WHEEL TIMING MECHANISM I Filed Jan. 8. 1948 5 Sheets-Sheet 1 w NIH [ll INVLW T 0R. jbrresf Jzzlzarz CZzldwelL dttorrze s Sept. 9, 1952 F. J. CALDWELL 2,609,680

HAIR SPRING AND BALANCE WHEEL TIMING MECHANISM Filed Jan. 8, 1948 5 Sheets-Sheet 2 dttorrz ys F. J. CALDWELL HAIR SPRING AND BALANCE WHEEL TIMING MECHANISM Sept. 9 1952 5 Sheefls-Sheet 3 Filed Jan. 8, 1948 IN VEIVTOR farres't Julian CZzZdua-IZL 13 fi 21% Gila iii!

M. rrzqys S p 9, 1952 F. J. CALDWELL 2,609,680

HAIR SPRING AND BALANCE WHEEL TIMING MECHANISM Filed Jan. 8, 1948 5 Sheets-Sheet 4 mum/7'02 A far/wt Jalz'omCaldwelL A es 5 S p 9, 1952 CALDWELL. 2,609,680

HAIR SPRING AND BALANCE WHEEL TIMING MECHANISM Filed Jan. 8, 194a r I 5 Sheets-Shet 5 INVENTOR firresi JIIZIOIL Caldwell,

diborrzeys i atenteci Sept. 9, 195 2- "UNITED -s TATES PATE OFFICE HAIR SPRING AND BALANGE WHEEL TIMING MECHANISM Forrest "Julian Caldweil; Chicagofl ll. Application Jen'ueey 8, 194B',-"seiie1'No. 1;247

minihg the period of vibrationofaspring nmss system or the'humberbf vibrations in any i'nteryalfof tithe inade thereby wherein-the niimber of "Vibrations "are individually counted-f and the intefval of tiih'eis measured, more particularly tef'sueh appafatus for dete inini'n'g the "period ofWib'iatiQn"of watch'and clock hair springs-arid attached *b'a'lance wheels; and it is an object; er, the invention to provide improved ap aratus Of tnisehereeter, I I

"It'is'a further obj't of jthe invention tofb'ro- Vid'inibfovedfabparatus of the foregoing chairmeg wherein the interval of time may be preset aha the *coufitin'g" er th'tibrations is ailtornatieen eteepea at" the end of L the i presetintei val. The accuracy "of atimepie'e using a balance itih 1" and hair spr'ing, WhethehWatch ore10ck, ae cls tda'lafeka xteht ujpon "the'chaIracters'of the ha'lancewheefandhaifspring. The fifimli'i" f 'vibiati'dn's 61" OSCillafiOzis f0 and fro whichthe balance wheel makes determines-the hii'nibf 6f revolutio s ni'ade by"th'e"f timepiece s fi eh finte'rvel or time. i Thus-1r "the bele'nee wheelie Vibi'atin'g too fast; th'efltiinepiece will runfest, "an if 'thebalance "wheel is "funsince this? point deter hair-,T'bririg, "its'sfai" constant, ."erid'nth ererer thelbriedfefyi nj "er the "combined hair spr 'iziu'geleriee hli point'er, ahd "the inumber of vibrations for interval :of "time, for example one minute, are.

manuall counted. A hair spring and balance whecL when 'once manually urged into'motion, will vibrate without externalhaid for approximately three minutes before it spends itself or ee'mes rest Inasmuchas the number of vibratiohs which the balance 'whe'el should make in one minuteis kno'wnfrom 'the number of teeth lowed 'tol'i ance, the operation is complete. However, it meyfbe that the craftsmanihasijgribped the sfiring' alt a poirit where'the sprin'g is to0 16ng and the second trial reveals -thc t thefflba-iance "Wheel is too slow. A thir d operation or thesatin; character will prob'ablyidetermine the counting: thereofat a. hai 'ticillar timefi counting *interva1 must be started at the emcee Y rioint a it 'whih thehair sl i ihg i sho'ifl'd -be' he1d.

The actual counting operationis tedious-and nerve-racking. -In aj rjeg'ular t'rain watch the balance wheel makesy five yibrations pei secbnd', or 300 vibrations per 1 minute-coiinting -b0th" thQ tick and=-tock" *movemefits. f-The "craftsman- H1 brati'ng the' 'hair springend baian e wheel t'hen must not only grip the very delicate hair-1 properly so that it is not distbi'tedf but he must start thebalance whel Vibif3tilig -and beg-in his time "the e'ounti'ngis begun, this IheceSSite IOOKIIIgfiIt the balance wheeland the timiI-I'Q d.

vice at the same instant. After the 01 )eiqitiell is begun; there-4s thesituation of having toccunt. as many asfive vibi'ationsa seeohd withoiit -misstodeVeldpfa sen$e-oftiniihg; wa chm p vibrators frequently use such methods a gt m c;

---- ssuming that re determine theprepereidm pemtw er theamu impairs the accuracy thereof and may even make it completely useless. Accordingly, it is a further object of my invention to provide improved apparatus for counting the vibrations of hair springs and the attached balance wheels where the counting operation and the time interval of counting may be carried out by the apparatus and the human factors are largely eliminated.

In apparatus according to one form of the invention, photoelectric means including a relatively narrow beam of light which may be interrupted by the balance wheel spoke has been provided, the light interruptions actuating means for counting the vibrations. A holding means for the watch hair spring has been provided so that the spoke of the balance wheel can vibrate into or through the beam of light. Since the hair spring. is a spiral, it is evident that the point of holding the hair spring determines the orientation of the balance wheel spoke relative to the light beam.

' That is, if the spring, when gripped at one point,

1 cor'dingly, it is'a further object of my invention to provide improved apparatus of the foregoing character for properly fixing the orientation of V a watch balance wheel relative to the vibration counting apparatus irrespective of where the hair spring is held.

, In carrying out the invention in one form, apparatus for timing a hair spring and the attached balance wheel including a spoke is provided comprising a hard surface upon which one end of the balance wheel shaft is adapted to pivot, means for gripping a watch spring at some point along its length to support the balance wheel shaft on said hard surface, a counter, photoelectric means operative when said balance wheel vibrates to actuate the counter, and tim ing .means for predetermining the interval of counter operation. 7 V i For a more: complete understanding of the invention, reference should be had to the accompanying drawings in which:

Figural is a front viewof hair spring and balance wheel vibrating apparatus embodying the invention;

,Fig. 2 isa side view partially in section of the apparatus shown in Fig. l; v i g Fig. 3 is a top. view taken substantially in the direction or" the arrows 3-3 of Fig. 2;

Fig. 4 is a view on a largerscale taken substantially in the direction of the arrows 4-4 of Fig. 3;

Fig. 5 is a viewtaken substantially in the direction of the arrows 55.of Fig. i;

Fig. 6 is a top view on an enlarged scale of the hair spring gripping mechanism;

Fig. 7 is asectionalview taken substantially in the direction of the arrows F of Fig. 6

Fig.3 is a side view: on an enlarged scale'of a modified form of hair spring gripping mech n mi .Fig 9 is a sectional view takensub'stantially the direction of the arrows QP-Bof Fig. 8;.

iii comprising a frame I I supporting in operative relationship with each other a photoelectric pickup I2, a housing l3 containing a relay and amplifier cooperating With the photoelectric pickup, and a sub-housing ltl enclosing timer mechanism it, a counter 16,, a light source ll, and supporting hair spring gripping and moving means It. The light source ll provides a beam of light receivedby the photoelectric pickup, which beam of light is interrupted or modified by the spoke of a balance wheel. These interruptions or modifications give rise to impulses which are received by amplifying and relay apparatus l3 and in turn energize counter is to count the number of V1- brations which the balance wheel makes, the timing apparatus I5 being adapted to stop the functioning of the counter after a predetermined length of time, as will be more fully explained.

The sub-housing l4 includes a removable cover i9 substantially centrally of which there is provided an opening having a stepped edge within which is received a circular disc 2| of a smooth,

hard material such for example as glass. A small I opening'at the center of disc 2i is fitted with a metal bushing 22 for determining the dimensions of the light beam from light source H. The surface of plate 2i forms a bearing for one end of the shaft or verge of a balance wheel 23, while the balance wheel and the combined hair spring 2d are supported by having one end of the hair spring held or gripped by the jaws 25. The gripping jaws are prevented from interfering with the action of a hair spring during vibrating movements thereof, inasmuch as the gripping jaws are raised vertically by the mechanism l8, causing the hair spring to take an inverted conical form, as may be seen best in Fig. 4 whereby the second hair spring coil lies below the gripping jaws and does not come into contact therewith during the vibrating movements. The photoelectric pickup l2, enclosing a photocell l0, and the light source llaresoiorientedrelative to each other than the beam of ligh't 2e, passes inside of the balance 7 Wheel riniand yet avoids the coils of the hair Fig. lQis a diagrammatic representation oi the apparatus embodying the invention;

Fig. 11 is a fragmentary view of' the counting mechanism, and e Q I Fig. 121s a fragmentaryview on an enlarged scaleof the timing mechanism. f

lteferring to the drawings, the invention is shown as embodied in a timepiece hair spring and talafmel h ly btaiiee see ,l e ei e pa a us spring. v

The mechanism 18 for gripping and holding the hair spring and attached balance wheel consists of a vertical stud 21, a rack'ZB movable vertically relative thereto by a pinion 29, a rack 31 supported on rack 28 and movable horizontally relative thereto by a pinion 32, a downwardly ex tending" shaft or post 33 pivotally mounted at the outer end of rack Li and a yoke 34 extending horizontally from, and attached to, post 33, the gripping jaws 25 being supported at the outer endfof yoke 34.

Vertical stud 2'! is rigidly attached to a thin annular ring 35 rotatably mounted in a groove in top'memb'er l9, ring 35 being. held within the groove by any desired means, such for example as the heads of screws 36, as shown. By virtue of pinion 29 supported relative t rack 28'by straps't'l, which also hold'rack 28 relative to stud 21, the rack128 is vertieally movable by means of .aknob 38." 1Vertica'lmovements of rack 28 carry rack 31 and thus the yoke 34 andjgrippingjavvs "25 vertically. Sufficient friction'exists between the variouspartsto hold rack ZBin'anY vertical position. jaws relative to the hair "spring coils' ma'y be adjusted vertically as desired while still having the lower end ofjthe' balance wheel verge bearlightly on'thesurfa'ce of disk 2i. Radial movements of rackBl efiected'by pinion 32 and the associated Hence, the i position of the "gripping meted radial position relative to the opening through bushing 22. Rack'"3l' isfsupported atop rack '28 by means of pinion 32 "and strap members 41'. as shown, and sufficient friction "exists between thefmen bers to hold rack 31 in any position L The end of a hair spring chosen at random rnaybear 'anydirectional relationship to the positime: the balance wheel spoke, Tobring about the desired position of the balance Wheel spoke 43, ring '35 may be moved circumferentially (i. 'e., rotated around its eenterfandyolsei i may be pivoted about stud"33 as 'ajcenterbvmeans 'of d 4 "a tac ed t t stu n F s- 13 and 5 spoke 43 is shown in one position of operation by the"solid lines Fig. 3 the structure 1 8 is shown in a second position bythedotted lines. It IS evident thatthe positionqf spokef43 is also changed relative to the opening in bushing '22. To obtain proper functioningof 'theapparatus, it may be found that thebeain of light shouldcbe interrupted from the side rather than n-om the front. Hence, 'ifthe position shown by the dotted lines was'the first one obtained, then it is o bvious that the position of the mechanism may be changed to that shown by the solid lines. In Fig. 5 yoke 1 34 is shown in a second positionby the dotted lines. ;I fperchance the i itial'positionof the yoke 34 with the attached jbalance wheel {is that shown by the dotted lines' where spoke 4a is far from bushing 22, evidentiy a ay bemoved to the position shownby the solidlines. The combination for the circumferential movemerits of ring 35, pivotal movements of yolge34, and radial movementsof'rack :31, bring the spoke 43 of any balance wheel intothe proper position relative to thelight beam 26, Balance wheels cf different diameters maybe accommodated by the radial movements of rack and pinions -3'l and'32.

I he yoke'34 comprises a pairof flat plates 44 and 45*spaced apart b p0sts46 and held thereto by screws 41. Plates 44 and 45 are "generally sector "shaped with resilient tohgues at jo nejend the tongues having holes through whichthe iewer end of post 33 may received. In"alignrnent with theholesthrough the tongues is a sleeve 48 serving to space the fingers apart. The yoke 34 is held to the stud by the friction between the holes: through the tongues and the post, and will turn therewith whenever the post is rotated by heads of knob 42, Theupper plate 44is-sn1aher than lower 'plate 45, as may beseen best in Figs. 1 it y i i thefouter end. thereof and adjacent the left side of lower plate, is an upwardly "bent menitier ae havi g a hole therethrough' within whic h flis received the base "51 :of the structure forming ripping jaw; 25. 'Mernber 49 suiilciently rigid andfinmly attached to plate 45 so that it willfreniain in its vertical position, and the'base 5i attachedto. member 49 isuch as by jpressfltor other suitable-means, for example,

"soldering.

1 e ies ip n S turai i1 idie Hand base it, preferably may v be "formed'as a m r? t uct r an si h wni a S 1- low'cylindrical rnernber-and the jaws are flat members'forrned by machining away-a portion of 'thecylindrical material. The jaws are separated by a very thin'sp1it52 but normally the jaws are closed with vtheir faces directly abutting each other due to the resiliehce of the jawmembers. A tubei53-zisslidably received within 'base 51 "and is: provided with iagrounded front ledge "54. ;JThe

inside su ace 55 ref he-J w members, against which the front edg 54 abutsfare alSo curved or tapered so that whenthe front edge 541s forced against surfaces 55 during-operation 'of' the str ic ture, the jaw members are forced apartga-n'd when frontedge 5 4 of the aboveis movedaway from surfaces 55 the jaws come together. Sleeve 53 may be moved rearwardly or forwardlyby means of a probe inserted into a conveniently providedhole 60. H fl H i A radial bar 56 is pivotally mounted at its rear end adjacent the rearfportion *0; plates 44 on a shaft, 7. and ext nds ward y sqf ha it protrudes beyond the extremity ofupperplate- 44. The outer end of bar 5E -includesathiinl1b screw 58 and afhole 594 so that the inner 'end er the thumb screw may beyisible. A'horizontai hole intersecting with hole! 59 is also provided through the outer end of bar 56. H e l T la r p n s u t e nd ba 5 l by yoke 34 operates as follows; Referring ore particularly to 'Eigsr5 andfi, the "hair spring 24 is showngrippedbyjawsfi. Thehair s'pring passes through tube 53 and the innerendtherebf is received through thehorizo tal hole 'in the outer endof bar 56 and is clamped thereto by means of the thumb s crew5 8, When'i'tis desired to change the gripping poslitignfon the hair spring to shorten it, tube 53 is pushed forwardly to hold jaws 25 apart and bar is moved clock-- wise to pull the hair spring 24 through theja'ws. After the desired movement: is made, tube 53 is moved toward theright, whereupon thejaws again grip the spring. When it is desired to lengthen the spring, tube-5 3is again moved-forwardly to release the gripping 'jaws and "bar "56 is moved countereloekwiseto push the hair spring outwardly v through the grippi g jaws until the desired position is reached 'whereupon tube 53 is again moved toward the right whereuppnthe jaws grip the spring. The slit 52 between jaws 25 is perfectly straight ,and forme'dso asvtpli'e in line with the axis of tube {53 sofithat when spring 24is grippeditmay bef'gripped along'the n ent h eto sea ot t niu it d Withthestructure as thus fardescribed, hair spring 24 maybe gripped at anydesired poiiit and the hair spring and balance wheel may be moved into position relativ'g 'to bushing -2'2fso that the balance wheel spoke 4; may vibrate across or into the'beam of light coming through bushing. Moreover, the, verticalposition of the hair spring maybe so adjusted that the balance wheel shaft rests on thesurface of member 21 and alsoremains out of the line formedby light beam 25. When the hair spring is s gripped, it maybe setjntomotion by means of aprobe and with the apparatusto befdescribed the number of vibratipns may be;counted Referring to Fig. 10, the re is-shown asch'ematic diagram of the complete apparatus for counting the vibrationsof thebalanoe'wheeiig once-it'has been set in motion. The balancewheelfis so setthatits spoke vjibratesirito the tamer light 26 formed by the incandescent source l1 seem as a 'eohventional lamp supplied 0 with turrets "through the transformerte, the light beam falling upon a photoeleetriefcell ION-supported in pickup l2, Figs. 1 and 2), meeigeaisrrem'wmen are fed to an amplifier 6| through conductors 62 and 63. The amplifiedsignals are fed to .a coil 64 ofa relay'fi'5 through conductors '66 and operation is supplied from a voltage source 80 which, for example, may be 110 volt alternating current. When it is desired to start theapparatus functioning, a switch 69 is closed thereby supplying power to amplifier GI through the circuit beginning with source 80 and including the conductors 1i, I2, I3, I4, I5, it, the fuse ii, and

the conductors l8 and I9. On completing this same circuit, a circuit is completed to a signal light 8| through conductors 82 and 83, the signal lamp indicating that the amplifier is receiving current and is heating up, and consequently after a short interval the apparatus is in condition to function. Closing switch 60 also completes a circuit to transformer 59 from source through conductors II, 72, 8 3, 95, through primary winding 86 of the transformer, through conductors 81, I5, 'IG, fuse TI, and conductors I8 and I9. Consequently, light source I? is energized and the beam of light 26 is in existence. Timer I5, shown enclosed in Figs. 1 and 2, is illustrated schematically in Fig. as comprising the synchronous motor 88, a train of gears 89, a cam 9i, and a pointer 92. The train of gears 39 is connected by means of a shaft to synchronous motor 93, and the last gear 93 of the train is connected by means of a frictional clutch and shaft to cam 9i and pointer '92. Referring to Fig. 12, pointer 92 is shown fixed to a shaft 94 by a set screw 95, which however is only exemplary. The other end of shaft 94 is attached to gear 99 by means of a flat plate 95 and bowed plate 97, these plates holding gear 93 to shaft 90 by means of riveting over the end of the shaft. Due to the bowing of plate 9?, plates 99 and 9'! grip gear 93 relatively lightly so that pointer 92 may be turned without turning gear 99 inasmuch as this gear is coupled through the gear train 89 to the synchronous motor. But when gear 93 is rotated by the synchronous motor, pointer 92 and cam SI, also firmly attached to shaft 94, rotate therewith.v Cam 9i, in its periphery, is provided with a notch 90 adapted to receive a corresponding protuberance 99 on a leaf spring IOI, the leaf spring being provided with a contact I00 at one end for engagement with a contact I001; connected to a conductor I92. Associated with pointer 92 is a dial plate I93 graduated in any units, for example minutes, and as shown is, graduated from 0 to 6 minutes.

Synchronous motor 02 is adapted to run always in the same direction which is such that pointer 92 moves clockwise. Thus, if pointer 92 is moved to 1 minute, cam BI is rotated so as to move protuberance 99 out of notch 98 and thereby close contacts Hi8 and I00a. Then, if motor 88 is energized, as will be described subsequently in this specification, the operation of the motor causes pointer 92 to move from 1 towards 0, cam 9! moving correspondingly, and when the pointer reaches 0, notch 98 will receive protuberance 99 and thereby open the contacts since spring IOI isresiliently made. Cam SI and pointer 92 are fixedly mounted relative to each other so that the rotation of notch 98 to a position indi-' cated by moving the pointer to any number on dial I03 determines the length of time the synchronous motor runs before notch 90 is returned to a position where it will receive protuberance 99. Inasmuch as synchronous motor 88 always runs. at the same speed, it is apparent that the distance cam 9| has to rotate to eiiect opening of contacts I00 and I00a, is indicative of the time elapsed.

Synchronous motor 88 may be energizedto begin the timing operation only after pointer 92 has been turned to a desired position, for Example 1 on dial I03, the switch 99 has been closed to warm up the amplifier and to form beam of light 26, and balance wheel 23 has been set in motion. Thereafter switch I04'is closed which energizes motor 08 and also the actuating mechanism of counter It so that the timing and counting operations begin at the same time. The circuit for energizing motor 98 is as follows: From source 80 through conductors II, I2, I05, the winding of motor 88,- ccnductors I96 and I232, contacts I00a, I00, spring IIlI, conductor I07, switch I04. conductor I08, fuse'l'l, conductor 08, switch 69, and conductor I9 to source 80.' Counter I6 is actuated by an electromagnet including coil I09 energized also after switches 69 and I09 have been closed through the following circuit: From source 00 through conductors 'II, I2, 84 and IIO, coil I09, conductor III, contacts 68, conductors II2, I06 and I02,contacts I00a, I00, spring IOI, conductor I02, switch I04, conductor I08, fuse 'I'I, conductor 03, switch 69, and conductor I9 to source 80. The contacts 99 of relay 95 are intermittently closed by impulses from amplifier BI as photoelectric cell '29 intermittently has its light cast off or decreased due to the vibration of balance wheel 23. The circuit described for counter coil I09 is completed only when contacts 50 are closed and consequently the actuating mechanism of counter 'IB is intermittently energized. The circuit for coil I99 and the circuit for motor 88 are not completed until switch Ifi i is closed, and are not effected by closing of switch 69.

When switch I04 is closed, a circuit is completed also to a second indicating lamp II3 which indicates that the complete mechanism is functioning. The circuit for lamp H3 is completed as follows: From source 89 through conductors II, I2, 94, and IM to lamp H3, and therefrom through conductors II5 and I02, contacts-I00a, I90, spring IOI, conductor I01, switch I94, conductor I00, fuse TI, conductor 98, switch 69, and conductor I9 to source 80. I I

The counter I6 is of a type comprising a series of round members I I6 bearing numbers from 1 to 9 and o thereon. Associated with members In; is a lever IN, a ratchet wheel IE8, and a pawl I I9 biased by a spring I2 I to engage the ratchet wheel. At one end of lever I !'I there is a link member I22 forming the core of coil I90, link I22 being biased in the direction shown by a compression spring I23. Whenever coil I99 is energized, lever II! is moved counterclockwise, thereby moving one of the indicating wheels IIB a distance of one num her, this being accomplished by'the closing of contacts 68. When contacts SB'open, .energization is removed from coil I09 whereby spring I23 urges the lever III to its normal position where pawl II9 can engage ratchet wheel H8 in a new position. In Fig. 11 the face view of the counter has been shown. The elements of the counter as described are well known, and thus are not disclosed in greater detail. I

The operation of the completed device is as follows: It isassumed that the watch hair spring 24 has been placed into gripping jaws 25 andthe position thereof and of the balance wheel 23 adjusted so that the spoke 43 comes into approximately the proper position relative to bushing 22. At this point switch 69 may be closedthereby energizing amplifier 9i, photoelectric. cell I0, and signal light 8I. The lighting of signal light 8| indicates that the apparatus is turned on and about ready to function. After a small interval or time for examplei,-several minutes, have elapsed allowingtheamplifier to warm up, pointer Mmaybe turnedto anypOSition, for Example 1 on-dial I03, this" movement causing, cam HI to rotatea corresponding. distance and thereby close contacts I09, IBM, these contacts being open when protuberance 99 .isreceived within notch 38. Now the balancewheel23isset into vibration bringing spoke 43 into light; beam .26, and switch" IMis closed. At{ the closingof thisswitch, signal light II3 comes on indicating that the counting. and timing function is under wayl, Also at the closing of switch I64 synchronous motor 88 begins to run and ener z ii n issup ie c011 whenever the contacts 68 are thereafter closed. With'each vibration of spoke 4 3 intothe beam of light, an impulse is received at the amplifier which is amplified and passed on to coil 64 whereby the relay 65intermittent1y closes-contacts 68. While motor 88 rotates in a direction moving the notch 98 towardthe protuberance 93, i, e., timing the interval of operation, counter. coil I09 isreceiving the impulses and moves one/of the wheelsone notch with each closure of contacts 68.

The foregoing operations take place simultaneously so that counter I6 counts the number of movements of the balance. wheel whilesynchronous motor 88 is timing the operation. When notch 98 reaches the protuberance 99 the contacts I60 and I 00a open, thereby de-energizing motor 88, and at the same time removing energy from coil I09 thereby simultaneously stopping the timing and counting operations. The end of the timing operation is indicated when the pointer 92 has returned to 0 whereupon signal light I I3 also oes out.

The operation described is a timing operation of one minute and during this time, depending upon the adjustments of the hair spring relative to the gripping jaws, as many as 300, or more or less, vibrations could have been counted by counter I6. Before making a regular timing operation as described, the apparatus may be set into operation by moving the pointer 92 to any desired position and closing switch I04 in order to adjust the position of the balance wheel spoke so that it comes into, crosses, or merely interferes with the beam of light as much as is necessary to get a sufficient variation in the light intensity to cause the apparatus to function properly.

If the point of gripping the hair spring has been such that too many vibrations were made, the hair spring is lengthened as described, the counting operation is then repeated, and as many similar tests made until the desired length is obtained. After the proper gripping point is obtained, the hair spring may be bent sharply at an angle across the front surface of the gripping .jaws thereby determining the exact location where the hair spring should be gripped after it is placed in the timepiece. In the manner described, an exact count of the number of vibrations is obtained inasmuch as the photoelectric cell is sensitive and can pick up variations in the amount of light caused by the balance wheel spoke, and relay 65, together with the counting mechanism, is sufficiently accurate and sensitive to function as many as six or more times per second. Counting the actual vibrations is an exact method of determining the point at which the hair spring should be gripped since it does not involve the accuracy of a standard of comparison, the number of vibrations which a balance wheel has to make being accurately known from thenumber of teeth on the various timepiece gears. i

Referring. to Figs. 1 and 2, the arrangementof the parts described in connection with Fig. 10- may be seen. Photoelectric cell Ill is mounted in pickup I2 and is attached to frame II' by means of a stand I38. The'pickup I2 is attached to this stand by means of a bolt and wing nut I24 so that the angle of the pickup may be changed if necessary for the beam of light 26 to squarely impinge upon the photo-sensitive sur-; face of the photo cell. The housing I3 cont ains the. amplifier 6| and the relay 65 which arefo f well known construction and are not disclosed in detailin this specification. while cover lfl of subhousing I4 holds mechanism for gripping nd. mj e bve n the ch. ha r: r n and balance wheel, the inside thereof houses; the various other mechanisms. Thus, for'eka nple, the transformer 59 is adapted to supp-ort'lthe socket I25. holding incandescent lamp II, The

counter, I6 is arranged at one 'endoffthe alongside fuse-fl! and the timer I5 is arranged at the frontofthe apparatus with pointer 92 externally visible, Also externally visible are the mamma an and mee riw ih theoff nd onbuttons for switches fid'and tild respectively! In Figs. 8 and 9 there is shown a modified structure for holding the gripping jaws. In this structure there is provided a hollow cylindrical member I26 within which are mounted a pair of rubber-rimmed rollers I21 and I28, the shaft I59 of roller I28 coming out and being provided with a knurled turning knob I3I. Cylindrical member I26 is closed on each side by plates I32 and I33 which also provide bearing surfaces for the shafts of rollers H1 and I28. Plates I32 and I33 have tongues I34 and I35 extending from each end and corresponding to the tongues at the end of yoke 34. Holes are provided in tongues I34 and I35 for receiving the lower end of stud 33, as already described. Cylindrical member I26 is'provided with holes I36 and I31, hole I36 being adapted to tightly receive the base 5I of the gripping jaw structure, this being by a press fit or by soldering, for example. The hair spring to be gripped by jaws 25 is passed through the tube 53 and is received between the engaging surfaces of rollers I28 and I21, the end of the spring passing out through hole I31. When it is desired to change the position of the hair spring, it is only necessary to release jaws 25 and turn knob I3I thereby moving the hair spring either to lengthen it or shorten it, as the case may be. When the desired change has been made, the tube 53 is moved to allow the jaws to grip the spring at the new point.

While particular embodiments of the invention have been shown, it will be understood, of course, that the invention is not limited thereto since many modifications may be made, and it is, therefore, contemplated by the appended claims to cover any such modifications as fall within the true spirit and scope of the invention.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. Apparatus for counting the vibrations of a hair spring and the attached balance wheel including a spoke comprising, a pair of expansible jaws for gripping said hair spring, means for expanding said jaws for releasing the grip thereof on said hair spring, an electric eye device including a beam of light, a pivotal support for 11 said jaws, first rack and pinion means for supporting and radially moving said pivotal support,

a second rack and pinion means for holding and vertically moving said first rack and pinion means, means movable about a circular path sub stantially centered about said expansible jaws for supporting said second rack and pinion means, said pivotal support, said first and second rack and pinion means, and said circularly @an electric motor and switch means for de-energizing said motor after a certain number of revo= lutions.

2. Apparatus for timing a hair spring and an attached balance wheel including a spoke comprising, a device for gripping said hair spring at some point along its length, electric eye apparatus including a beam of light, a counter controlled by said electric eye apparatus, means for predetermining the interval of counter operation,

, r 12 and adjustable supporting means for said grip ping device, said supporting means permitting pivotal movement of said gripping device about a pivot having a vertical axis and linear movement of said pivot along a horizontal'straight line, said gripping means having a pair of jaws for releasably holding said spring at any desired point thereon and a hollow tube arranged with one end thereof opening immediately behind said jaws for receiving and positioning the inactive end of said spring.

FORREST JULIAN CALDWELL.

REFERENCES CITED The following references, are of record in the file of this patent:

UNITED STATES PATENTS 

